U.S. Pat. No. 9,228,455 is incorporated herein by reference in entirety and discloses a marine engine for an outboard motor comprising a bank of piston-cylinders, an intake camshaft that operates intake valves for controlling inflow of air to the bank of piston-cylinders, an exhaust camshaft that operates exhaust valves for controlling outflow of exhaust gas from the bank of piston-cylinders, and a cam phaser disposed on one of the intake camshaft and exhaust camshaft. The cam phaser is connected to and adjusts a timing of operation of the other of the intake camshaft and exhaust camshaft with respect to the one of the intake camshaft and exhaust camshaft.
U.S. Pat. No. 7,673,604 discloses a valve mechanism that drives an exhaust valve with a valve lifter and an exhaust camshaft. Oil is supplied to a journal surface of the camshaft and a bearing supporting the camshaft journal surface through an axial oil passage formed in the camshaft. The bearing is defined by a cam bucket and a bearing main body. An oil collecting recess is defined between cam bucket and the bearing main body. An auxiliary delivery passage extends from the oil collecting recess to a sidewall of the bearing that is located adjacent to the valve lifter. A guide wall is formed in the sidewall to lead oil from an opening of the auxiliary delivery passage to a part of the valve lifter that generates a striking noise in the absence of buffering oil.